The invention relates to a device for supplying power to a motor vehicle, in particular a passenger vehicle or a motorcycle, and includes a plurality of electrochemical storage cells and/or double-layer capacitors. The storage cells and/or double-layer capacitors include a casing surface and, in the axial direction, a base surface and a cover surface, which are connected by the casing surface and each include electrodes.
Electrochemical storage cells and/or double-layer capacitors in operation can reach considerable temperatures so that cooling is necessary. The cooling of electrochemical storage cells is done from the outside. If a sufficient cooling cannot be ensured with sufficient certainty, then defects can quickly arise which cannot be reconciled economically with the requirements for service lifetime when used in automobiles.
It is thus the object of the present invention to provide a device for supplying power to a motor vehicle, in particular for the temporary driving of the motor vehicle by an electric motor, in which, through a cooling apparatus, sufficient cooling can be ensured with great certainty.
This object is achieved according to the invention by a device for supplying power to a motor vehicle, in particular a passenger vehicle or a motorcycle. The device includes a plurality of electrochemical storage cells and/or double-layer capacitors, the electrochemical storage cells and/or double-layer capacitors include a casing surface and, in an axial direction, a base surface and a cover surface, which base and cover surfaces are connected by the casing surface and each include electrodes. Adjacent to the casing surface of at least one of the storage cells and/or double-layer capacitors, a heat-conducting cooling apparatus is disposed which, although electrically insulated from the at least one storage cell and/or the double-layer capacitor, is in thermal contact with a first circumferential section of the casing surfaces and dissipates heat energy introduced by the casing surfaces of the at least one storage cell and/or the double-layer capacitor. Advantageous further developments are described herein.
In an advantageous manner the heat can thus be dissipated in the radial direction of the storage cell and/or the double-layer capacitor immediately at its point of origin when used in an automobile. The complexity of the construction is relatively low. Moreover, the device according to the invention is distinguished by a high service lifetime. The cooling apparatus's radial arrangement, in particular due to its large attachable surface, enables good thermal attachment of the storage cell and/or the double-layer capacitor to the cooling apparatus. Moreover, a simple, modular design is made possible in which many identical parts can be used.
The electrochemical storage cells are preferably lithium-based battery cells or nickel-metal hybrid batteries, which are distinguished by a high storage capacity with low volume. The storage cells and/or double-layer capacitors each include a circular, prismatic, rectangular, square, oval, or obovate cross section. In accordance with requirements, modules consisting of several storage cells and/or the double-layer capacitors can thus be formed which have a high packing density.
In a development of the invention, it is provided that between each of the two storage cells and/or the double-layer capacitors a carrier made of electrically insulating material, in particular PP, is disposed in such a manner that it abuts a second circumferential section of the casing surface of each of the two storage cells and/or the double-layer capacitors. The carrier can optionally be formed of a heat-conducting material, for example, filled silicone. Expediently a respective storage cell and/or a respective double-layer capacitor is in contact along its entire circumference either with the cooling apparatus or with the carrier. Due to this there is, along with good cooling, the advantage of a mechanically loadable seating of the storage cells and/or the double-layer capacitors. If the elasticity of the carrier can be adjusted, then there is furthermore a compensation of tolerance by the carrier.
In a further development, the cooling apparatus includes a heat-conducting half shell which has a surface shape complementary to the casing surface of the at least one storage cell and/or the double-layer capacitor and is in thermal contact with the at least one storage cell and/or the double-layer capacitor. Due to the heat-conducting half shell's surface shape complementary to the storage cell and/or the double-layer capacitor, outstanding cooling is possible. At the same time, the storage cells and/or the double-layer capacitors are fixed in addition by the shape of the half shells.
In particular, the heat-conducting half shell extends (in the axial direction) over a length of the casing surface, specifically a length which corresponds at least to the length of an active part of the storage cell and/or the double-layer capacitor. The active part of a storage cell is also called a “winding” or a “jelly roll.” Thereby, the reliability of the cooling is greatly increased.
According to a further development, the heat-conducting half shell is thermally coupled (in the radial direction) over a circumferential arc of preferably 150° to 180° with a respective casing surface. According to this development, an outstanding fixation of the storage cell and/or the double-layer capacitor with maximum heat dissipation is ensured.
In a further form of embodiment of the invention, it is provided that the heat-conducting half shell is thermally connected to a cooling wall of the cooling apparatus, where the heat-conducting half shell is disposed between the cooling wall and the at least one storage cell and/or the double-layer capacitor. The cooling apparatus of the device according to the invention is thus formed in two parts. In immediate thermal contact with the storage cells and/or the double-layer capacitors to be cooled are the half shells, which in turn dissipate the heat at a cooling wall. The two-part configuration of the cooling apparatus enables a constructively simple, in particular modular, design according to which the half shells can be adapted, with thermal optimization, to the shape of the storage cells and/or double-layer capacitors. Also, the transfer of heat to the cooling wall can be done with optimization, and in particular for a large number of storage cells and/or double-layer capacitors, in a simple manner.
The cooling wall can, in particular, include cooling ducts through which or around which there flows a heat-dissipating medium, in particular a coolant such as R 134a, carbon dioxide R 744, water, or air. Thereby, the dissipation of heat can always be ensured in a reliable and sufficient manner even with short-term peak loads of the storage cell. The cooling ducts can, for example, be integrated into a circuit of an air conditioning system of the motor vehicle.
The cooling wall can furthermore be enclosed by thermal insulation. For example, the cooling wall is provided with a preferably electrically operated air conditioning device which dissipates the heat energy and which preferably works according to the vaporizer process or Peltier process. Thereby, the device can be cooled reliably with little effort and substantially unaffected by the ambient temperature at the actual location at which the device according to the invention is disposed in the vehicle.
Expediently, the heat-conducting half shell and/or the cooling wall can be formed from aluminum, copper, a filled silicone, or another material which conducts heat well.
In another expedient development, it is provided that, between the heat-conducting half shell and the casing surfaces of the at least one storage cell and/or the double-layer capacitor, an insulating layer is disposed. The insulating layer serves to ensure electrical insulation of the half shell consisting of electrically conducting material with respect to the casing surfaces of the storage cell(s) and/or double-layer capacitor(s). The insulating layer can, for example, be formed from filled silicone, an epoxy resin, or another plastic, such as polyurethane, polyimide, or polyacrylate. The material strength of the insulating layer depends on tolerances of the storage cell and the voltage level of the device. Expediently, the layer thickness will be between 01. mm and 1 mm. The thermal conductivity is typically λ=0.5 to 5 W/(K m).
According to a further advantageous development, between the heat-conducting half shell and the cooling wall a heat-conducting paste, a heat-conducting foil, or a heat-conducting coating is provided. This provides for a defined heat transfer. Moreover, it is possible to prevent, at the transition surface, air pockets which can lead to local overheating and thus possibly to a defect in the device. The heat-conducting paste, the heat-conducting foil, or the heat-conducting coating is preferably electrically insulating and, in addition, compensates manufacturing tolerances for the clearance or fills clearances up. Thereby, good thermal contact is achieved even with the customary manufacturing tolerances and in case of vibrations. A heat-conducting foil includes preferably silicone with wax and/or ceramics as a filler or a mixture of various heat-conducting substrates and can include multi-layer coatings.
In an extension of the invention, it is provided that the carrier is provided with one or more cavities in areas which cannot assume a holding function. The one or more cavities can serve for active cooling with a coolant medium conducted through there or for passive cooling by heat convection. Furthermore, a reduction in weight is achieved.
It is furthermore provided that the heat-conducting half shell for forming defined surfaces for transferring heat to the cooling wall includes one or more cavities in the area of each of the two storage cells and/or double-layer capacitors disposed one over the other. Along with a reduction in weight, the cavities serve essentially to optimize the heat-conducting half shell's surfaces for heat transfer to the cooling wall such that a predefined force to which the arrangement must be exposed in order to ensure a certain contact pressure and in order to ensure the required cooling is not exceeded. The smaller the heat transfer surface is chosen, the lower it is possible to set the force with which the cooling wall must be pressed against the half shell. The size of the heat transfer surfaces, and thus the size of the cavities, are thus to be chosen as a function of the force to be applied. Expediently, the heat transfer surface is formed to be as small as possible so that the necessary force can be kept small.
It is furthermore provided that the plurality of storage cells in a module are connected in series and/or in parallel, where one module is formed of storage cells and/or double-layer capacitors disposed in vertical stacks of adjacent pairs, where a common carrier and at least one common heat-conducting half shell is provided for the storage cells and/or double-layer capacitors disposed in a vertical stack in groups of two.
According to a further development there is, between the cooling wall and the heat-conducting half shell, a plane in which the transfer of heat occurs and which is disposed obliquely in relation to the direction of gravity so that the module, in particular the heat-conducting half shell, is pressed by the force of gravity onto the cooling wall. By applying a defined force in the direction of gravity, the necessary force between the half shell and the cooling wall can be set. Should it be necessary in addition, a device can be provided which amplifies the force prevailing between the half shell and the cooling wall in the direction of the force.
In an extension of the invention, it is provided that at least one of the electrodes disposed in each of the storage cells and/or double-layer capacitors (in the so-called winding) consists of metal and is provided to a large extent over its entire surface with a metal layer. The metal electrode or the metal layer, in particular a metal foil, is connected in an electrically conducting manner via a connecting element to a terminal provided outside of the storage cell or outside of the double-layer capacitor. Along with this it is provided for further improvement of the cooling that a heat-conducting cooling plate, which is in thermal contact with a plurality of the terminals of the storage cells or the double-layer capacitors, dissipates the heat energy introduced by the metal electrodes or the metal layers of the electrodes to the terminal via the connecting element. According to this development, the radial cooling of the storage cells and/or the double-layer capacitors is supported by axial cooling.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawing.